The present invention generally relates to valve means for use in a fluid flow pipe.
A generally known solution for preventing back flow of a flow from a predetermined flow direction is to install a non-return valve. For example, a secondary flow pipe may be provided near the junction of the secondary flow pipe and a main flow pipe, so that the flow from the secondary flow pipe into the main flow pipe can be prevented from flowing back into the secondary flow pipe. The installation of an additional device in the piping is, however, arduous, requires substantial space, and is expensive.
WO 99/32816 discloses a different approach, in which a valve means is installed in the junction of the main flow pipe and the secondary flow pipe. This known solution comprises a separate valve body with flow pipe connections and a secondary flow pipe connection, whereby the flow opening of the secondary flow pipe is arranged to be closed by a mechanical flap. The known valve means, forming a separate entity, is difficult to install and its function is subject to disturbances and faults due to its complicated structure.
The object of the invention is to achieve a valve means, by which the above mentioned disadvantages are avoided and which provides for a reliable function by simple means. In accordance with the teachings of the present invention, the actual valve function is achieved in a simple manner provided by the structure or structure material of the valve means.
In accordance with an exemplary embodiment, the valve means comprises a body part, which can be fixed to the flow pipe. The length of the body part in the direction of the flow pipe is longer than the extension or length of the flow opening in the direction of the flow pipe, and the extension of the body part in a radial direction or the peripheral direction of the flow pipe is chosen larger than the extension of the flow opening in the radial direction or the peripheral of the flow pipe, whereby the body part can cover the flow opening.
The body part may be made of a resilient material so that it gives way to the flow from the flow pipe and so that it resumes its original position after the flow, whereby it covers said flow opening, prevents back flow and, depending on the circumstances it is used, does not form a barrier to the flow in the flow pipe.
In order to provide simple structure and installation, the body part may be cylindrical or sleeve like, whereby its outer diameter is substantially equal to the inner diameter of the flow pipe or a branch part of the flow pipe. The body part is advantageously attachable to the flow pipe, or to the branch part, by a connecting means.
The connecting means is advantageously formed of a first flange portion connected to the body part and extending in a first direction of the flow pipe, the inner diameter of which is substantially equal to the outer diameter of the flow pipe, and of a second flange portion extending in a second direction opposite to the first direction of the flow pipe, the inner diameter of which is substantially equal to the outer diameter of the flow pipe. Thus the body part of the valve means and its attaching element (i.e. the first flange portion and the second flange portion) may easily be formed into a unitary structure.
In order to ensure resistance to wear and a secure function, the valve means is advantageously made from a resilient structure that resumes its shape, such as a rubber material or the like. The valve means may also be pre-installed, such as into a separate pipe section connectable to the flow pipe or into a separate pipe junction connectable to a flow pipe and a secondary flow pipe.
The valve means is particularly advantageous when employed in a vacuum sewer system.